Evaluation of Some Indices of Potentially Mineralizable Nitrogen in Soil
Bibliographic record
Abstract
A series of soil N mineralization indices were evaluated using 153 samples chosen from arable fields representing a wide range of soil types, management practices, and climatic zones. These indices were compared against potentially mineralizable N (N 0 ) determined by aerobic incubation at 25°C for 24 wk. Three different pools of mineralizable N were recognized: Pool I, the mineralization flush on rewetting in the first 2 wk; Pool II, gross N mineralization in the next 22 wk; and Pool III, the potentially mineralizable N, predicted from the fitted curve, that did not mineralize during the incubation period. Pool I was highly correlated with CaCl 2 –N, KCl‐NH 4 , and KCl‐NO 3 , which extract soil mineral N. Pool III was significantly correlated with ultraviolet absorbance of NaHCO 3 extract at 205 and 260 nm (NaHCO 3 –205 and −260), Illinois soil N test, NaOH direct‐distillation N, and hot KCl‐NH 4 , which mostly extract hydrolyzable organic N. All indices except the mineral N based methods, phosphate‐borate buffer method, and microbial biomass C were significantly related to N 0 , which includes both Pools II and III. The NaHCO 3 –260, NaOH direct‐distillation N, and Illinois soil N test had the highest correlations with N 0 ( r 2 = 0.74, 0.61, and 0. 51, respectively). Total organic C and N represent long‐term changes in N 0 and were almost as effective in predicting N 0 as the other indices ( r 2 = 0.60 and 0.67, respectively); however, they would be expected to be less sensitive to short‐term changes in N 0 due to changes in soil management practices and history.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".